A South American trade bloc has adopted a measure closing its ports to vessels flying the flag of the Falklands Islands - the South Atlantic territory held by Britain, but claimed by Argentina.
The measure was agreed at a summit of Mercosur in the Uruguayan capital, Montevideo.
But President Jose Mujica of Uruguay said British civilian ships that supply the islands would still be allowed to use its ports.
The British Foreign Office said there was "no justification" for the action.
The Falklands flag is flown by 25 boats, mostly fishing vessels operated in joint ventures with Spanish companies.
The BBC reports the decision is the latest in a series by Latin American regional bodies designed to show solidarity with Argentina which claims sovereignty over the Falkland Islands, which it calls Las Malvinas.
Britain has held them since the 1830s and says their future is not negotiable. The two countries fought a brief war over the islands in 1982.
Britain has refused recent requests to re-open negotiations on the sovereignty of the Falklands.